Preference mapping and rheological properties of four nopal (Opuntia spp.) cultivars
Keywords:descriptive analysis, mucilage, acceptability, rheology.
The aim of this study was to identify the sensory characteristics that drive the preference of nopalitos consumers. Nopalitos from the cultivars Milpa Alta, COPENA F1, COPENA V1 and Tovarito (Opuntia ficus–indica), which are commercially important in Mexico, were physical, chemical and sensory characterized to explain their acceptability by consumers. The rheological behavior of aqueous dispersions made from the mucilage of each one of the four nopal cultivars was evaluated. Color, firmness, moisture, titratable acidity and mucilage content were measured in fresh nopalitos. Frequency sweeps and flow curves of the mucilage dispersions were done. A descriptive analysis and an acceptability test were carried out with cooked nopalitos. The heterogeneity of the four nopal cultivars stood out. Significant differences were found among cultivars for seven physical and chemical characteristics (lightness, saturation index, hue angle, cuticle firmness, firmness within the tissue, moisture and titratable acidity), for their plastic viscosity, important variable of rheological behavior, and for 12 sensory attributes (lightness, moist appearance, visual sliminess, green odor, elasticity, firmness, sourness, saltiness, green flavor, leatheriness, chewiness and sliminess in mouth). Milpa Alta, COPENA F1 and Tovarito cultivars were similarly accepted by consumers, whereas COPENA V1 had less acceptability. It was concluded that nopalitos acceptance can be predicted based on their physical, chemical and sensory attributes; moreover, that textural and visual characteristics were the variables with major influence on acceptability.